Various types of single-sheet feeding apparatus to feed, automatically, single sheets to typewriters, printers, and other office machines, have been proposed. For many installations, it is desirable to be able to selectively associate the single-sheet feeder with an already existing apparatus, so that the feed of the single sheets can be controlled by machine operation of the office machine, without, however, interfering with manual feed of sheets, or requiring purchase of a new, or different apparatus capable of automatic sheet insertion. Different manufacturers and different types of office machines requiring single sheets have different dimensions and different arrangement of capabilities. This makes it difficult to provide an attachment element to such office machines of various manufacturers and to control sheet feeding from the different types of office machines.